I could actually see this being a cantrip for a bard or arcane trickster. It’s almost innocent in its mischief but would be a worthwhile hindrance on the battlefield.

For shoes without laces and creatures without shoes it could simply loop magical string around them.

Prob just a cut to movement with a dex save at the start of every move (like once per turn but they can avoid it by choosing not to move). Doesn’t need to be a high save, but if they fail, they trip.

Since it’s a cantrip they can remove the string with an action, and they last a number of turns equal to caster level.

I’d also love to see a DM be creative with how much it effects certain creatures. Centipede? Probably a little pissed but not too hindered by stumbling on one pair of legs. 1 legged Pete? Completely unaffected as he jumps at you with his 1 leg.

Boot Loops, when you can’t afford Fruit Loops.